The invention relates to a shaft rod for setting up a heald shaft for a weaving machine.
Heald shafts in weaving machines are disposed to accommodate a large number of healds, whereby each heald has a thread eye in order to guide a warp thread. Additional warp threads run between the healds. As a result of the up-and-down movement of the heald shaft the warp threads guided by the healds can be moved out of the plane of the remaining healds, as a result of which a shed is created into which the weft thread can be carried.
In most cases, each heald has at least two horizontal shaft rods that are parallel to each other and that have ends that are connected to each other by vertical lateral supports. Thus, the heald shaft forms a rectangular frame. Each of the upper and the lower shaft rods carries a heald mounting rail that consists, e.g., of steel. The healds have terminal eyelets that are used to hold them on the heald mounting rails.
In most cases, the heald shafts and the heald mounting rails are manufactured separately and subsequently connected to each other. To accomplish this, document DE 10 2004 037 717 B3 suggests the use of rubber cords. To do so, the shaft rod is provided with a groove that extends into a foot of the heald mounting rail. The rubber cord that is inserted in axially expanded state into the remaining space is used for clamping the foot in place in the groove. If the rubber cord is relaxed, it is shortened and its diameter is thus increased, so that it wedges the foot of the heald mounting rail into the groove of the shaft rod. However, to do so, it is necessary that the rubber cord be able to contract accordingly along the entire length. In addition, the heald mounting rail is provided with a relatively complexly formed, precisely fitting foot in order to effect a correct positioning of the rails and also a positive-locking engagement for securing said rail.
Document JP 59-149981 discloses a heald mounting rail that has a trapezoidal foot. Depending on the embodiment, this foot is manufactured separately and riveted to the heald mounting rail or made in one piece with said heald mounting rail. The shaft rod comprises an appropriately shaped accommodation space into which the mounting rail foot is inserted and secured, for example, by gluing, so that a thin glued joint is formed.
This type of connecting technique requires that the parts to be connected to each other display narrow tolerance ranges.
Considering this, it is the object of the invention to provide a possibility for the manufacture of shaft rods for healds by means of a reliable process.